package com.kudo.util.apache.codec.binary;

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import com.kudo.util.apache.codec.Charsets;
import java.io.UnsupportedEncodingException;
import java.nio.charset.Charset;

/**
 * Converts String to and from bytes using the encodings required by the Java
 * specification. These encodings are specified in <a
 * href="http://download.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">
 * Standard charsets</a>.
 *
 * <p>This class is immutable and thread-safe.</p>
 *
 * @see CharEncoding
 * @see <a
 * href="http://download.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard
 * charsets</a>
 * @version $Id: StringUtils.java 1435550 2013-01-19 14:09:52Z tn $
 * @since 1.4
 */
public class StringUtils {

    /**
     * Calls {@link String#getBytes(Charset)}
     *
     * @param string The string to encode (if null, return null).
     * @param charset The {@link Charset} to encode the {@code String}
     * @return the encoded bytes
     */
    private static byte[] getBytes(final String string, final Charset charset) {
        if (string == null) {
            return null;
        }
        return string.getBytes(charset);
    }

    /**
     * Encodes the given string into a sequence of bytes using the ISO-8859-1
     * charset, storing the result into a new byte array.
     *
     * @param string the String to encode, may be {@code null}
     * @return encoded bytes, or {@code null} if the input string was
     * {@code null}
     * @throws NullPointerException Thrown if {@link Charsets#ISO_8859_1} is not
     * initialized, which should never happen since it is required by the Java
     * platform specification.
     * @since As of 1.7, throws {@link NullPointerException} instead of
     * UnsupportedEncodingException
     * @see <a
     * href="http://download.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard
     * charsets</a>
     * @see #getBytesUnchecked(String, String)
     */
    public static byte[] getBytesIso8859_1(final String string) {
        return getBytes(string, Charsets.ISO_8859_1);
    }

    /**
     * Encodes the given string into a sequence of bytes using the named
     * charset, storing the result into a new byte array.
     * <p>
     * This method catches {@link UnsupportedEncodingException} and rethrows it
     * as {@link IllegalStateException}, which should never happen for a
     * required charset name. Use this method when the encoding is required to
     * be in the JRE.
     * </p>
     *
     * @param string the String to encode, may be {@code null}
     * @param charsetName The name of a required
     * {@link java.nio.charset.Charset}
     * @return encoded bytes, or {@code null} if the input string was
     * {@code null}
     * @throws IllegalStateException Thrown when a
     * {@link UnsupportedEncodingException} is caught, which should never happen
     * for a required charset name.
     * @see CharEncoding
     * @see String#getBytes(String)
     */
    public static byte[] getBytesUnchecked(final String string, final String charsetName) {
        if (string == null) {
            return null;
        }
        try {
            return string.getBytes(charsetName);
        } catch (final UnsupportedEncodingException e) {
            throw StringUtils.newIllegalStateException(charsetName, e);
        }
    }

    /**
     * Encodes the given string into a sequence of bytes using the US-ASCII
     * charset, storing the result into a new byte array.
     *
     * @param string the String to encode, may be {@code null}
     * @return encoded bytes, or {@code null} if the input string was
     * {@code null}
     * @throws NullPointerException Thrown if {@link Charsets#US_ASCII} is not
     * initialized, which should never happen since it is required by the Java
     * platform specification.
     * @since As of 1.7, throws {@link NullPointerException} instead of
     * UnsupportedEncodingException
     * @see <a
     * href="http://download.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard
     * charsets</a>
     * @see #getBytesUnchecked(String, String)
     */
    public static byte[] getBytesUsAscii(final String string) {
        return getBytes(string, Charsets.US_ASCII);
    }

    /**
     * Encodes the given string into a sequence of bytes using the UTF-16
     * charset, storing the result into a new byte array.
     *
     * @param string the String to encode, may be {@code null}
     * @return encoded bytes, or {@code null} if the input string was
     * {@code null}
     * @throws NullPointerException Thrown if {@link Charsets#UTF_16} is not
     * initialized, which should never happen since it is required by the Java
     * platform specification.
     * @since As of 1.7, throws {@link NullPointerException} instead of
     * UnsupportedEncodingException
     * @see <a
     * href="http://download.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard
     * charsets</a>
     * @see #getBytesUnchecked(String, String)
     */
    public static byte[] getBytesUtf16(final String string) {
        return getBytes(string, Charsets.UTF_16);
    }

    /**
     * Encodes the given string into a sequence of bytes using the UTF-16BE
     * charset, storing the result into a new byte array.
     *
     * @param string the String to encode, may be {@code null}
     * @return encoded bytes, or {@code null} if the input string was
     * {@code null}
     * @throws NullPointerException Thrown if {@link Charsets#UTF_16BE} is not
     * initialized, which should never happen since it is required by the Java
     * platform specification.
     * @since As of 1.7, throws {@link NullPointerException} instead of
     * UnsupportedEncodingException
     * @see <a
     * href="http://download.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard
     * charsets</a>
     * @see #getBytesUnchecked(String, String)
     */
    public static byte[] getBytesUtf16Be(final String string) {
        return getBytes(string, Charsets.UTF_16BE);
    }

    /**
     * Encodes the given string into a sequence of bytes using the UTF-16LE
     * charset, storing the result into a new byte array.
     *
     * @param string the String to encode, may be {@code null}
     * @return encoded bytes, or {@code null} if the input string was
     * {@code null}
     * @throws NullPointerException Thrown if {@link Charsets#UTF_16LE} is not
     * initialized, which should never happen since it is required by the Java
     * platform specification.
     * @since As of 1.7, throws {@link NullPointerException} instead of
     * UnsupportedEncodingException
     * @see <a
     * href="http://download.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard
     * charsets</a>
     * @see #getBytesUnchecked(String, String)
     */
    public static byte[] getBytesUtf16Le(final String string) {
        return getBytes(string, Charsets.UTF_16LE);
    }

    /**
     * Encodes the given string into a sequence of bytes using the UTF-8
     * charset, storing the result into a new byte array.
     *
     * @param string the String to encode, may be {@code null}
     * @return encoded bytes, or {@code null} if the input string was
     * {@code null}
     * @throws NullPointerException Thrown if {@link Charsets#UTF_8} is not
     * initialized, which should never happen since it is required by the Java
     * platform specification.
     * @since As of 1.7, throws {@link NullPointerException} instead of
     * UnsupportedEncodingException
     * @see <a
     * href="http://download.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard
     * charsets</a>
     * @see #getBytesUnchecked(String, String)
     */
    public static byte[] getBytesUtf8(final String string) {
        return getBytes(string, Charsets.UTF_8);
    }

    private static IllegalStateException newIllegalStateException(final String charsetName,
            final UnsupportedEncodingException e) {
        return new IllegalStateException(charsetName + ": " + e);
    }

    /**
     * Constructs a new
     * <code>String</code> by decoding the specified array of bytes using the
     * given charset.
     *
     * @param bytes The bytes to be decoded into characters
     * @param charset The {@link Charset} to encode the {@code String}
     * @return A new <code>String</code> decoded from the specified array of
     * bytes using the given charset, or {@code null} if the input byte array
     * was {@code null}.
     * @throws NullPointerException Thrown if {@link Charsets#UTF_8} is not
     * initialized, which should never happen since it is required by the Java
     * platform specification.
     */
    private static String newString(final byte[] bytes, final Charset charset) {
        return bytes == null ? null : new String(bytes, charset);
    }

    /**
     * Constructs a new
     * <code>String</code> by decoding the specified array of bytes using the
     * given charset.
     * <p>
     * This method catches {@link UnsupportedEncodingException} and re-throws it
     * as {@link IllegalStateException}, which should never happen for a
     * required charset name. Use this method when the encoding is required to
     * be in the JRE.
     * </p>
     *
     * @param bytes The bytes to be decoded into characters, may be {@code null}
     * @param charsetName The name of a required
     * {@link java.nio.charset.Charset}
     * @return A new <code>String</code> decoded from the specified array of
     * bytes using the given charset, or {@code null} if the input byte array
     * was {@code null}.
     * @throws IllegalStateException Thrown when a
     * {@link UnsupportedEncodingException} is caught, which should never happen
     * for a required charset name.
     * @see CharEncoding
     * @see String#String(byte[], String)
     */
    public static String newString(final byte[] bytes, final String charsetName) {
        if (bytes == null) {
            return null;
        }
        try {
            return new String(bytes, charsetName);
        } catch (final UnsupportedEncodingException e) {
            throw StringUtils.newIllegalStateException(charsetName, e);
        }
    }

    /**
     * Constructs a new
     * <code>String</code> by decoding the specified array of bytes using the
     * ISO-8859-1 charset.
     *
     * @param bytes The bytes to be decoded into characters, may be {@code null}
     * @return A new <code>String</code> decoded from the specified array of
     * bytes using the ISO-8859-1 charset, or {@code null} if the input byte
     * array was {@code null}.
     * @throws NullPointerException Thrown if {@link Charsets#ISO_8859_1} is not
     * initialized, which should never happen since it is required by the Java
     * platform specification.
     * @since As of 1.7, throws {@link NullPointerException} instead of
     * UnsupportedEncodingException
     */
    public static String newStringIso8859_1(final byte[] bytes) {
        return new String(bytes, Charsets.ISO_8859_1);
    }

    /**
     * Constructs a new
     * <code>String</code> by decoding the specified array of bytes using the
     * US-ASCII charset.
     *
     * @param bytes The bytes to be decoded into characters
     * @return A new <code>String</code> decoded from the specified array of
     * bytes using the US-ASCII charset, or {@code null} if the input byte array
     * was {@code null}.
     * @throws NullPointerException Thrown if {@link Charsets#US_ASCII} is not
     * initialized, which should never happen since it is required by the Java
     * platform specification.
     * @since As of 1.7, throws {@link NullPointerException} instead of
     * UnsupportedEncodingException
     */
    public static String newStringUsAscii(final byte[] bytes) {
        return new String(bytes, Charsets.US_ASCII);
    }

    /**
     * Constructs a new
     * <code>String</code> by decoding the specified array of bytes using the
     * UTF-16 charset.
     *
     * @param bytes The bytes to be decoded into characters
     * @return A new <code>String</code> decoded from the specified array of
     * bytes using the UTF-16 charset or {@code null} if the input byte array
     * was {@code null}.
     * @throws NullPointerException Thrown if {@link Charsets#UTF_16} is not
     * initialized, which should never happen since it is required by the Java
     * platform specification.
     * @since As of 1.7, throws {@link NullPointerException} instead of
     * UnsupportedEncodingException
     */
    public static String newStringUtf16(final byte[] bytes) {
        return new String(bytes, Charsets.UTF_16);
    }

    /**
     * Constructs a new
     * <code>String</code> by decoding the specified array of bytes using the
     * UTF-16BE charset.
     *
     * @param bytes The bytes to be decoded into characters
     * @return A new <code>String</code> decoded from the specified array of
     * bytes using the UTF-16BE charset, or {@code null} if the input byte array
     * was {@code null}.
     * @throws NullPointerException Thrown if {@link Charsets#UTF_16BE} is not
     * initialized, which should never happen since it is required by the Java
     * platform specification.
     * @since As of 1.7, throws {@link NullPointerException} instead of
     * UnsupportedEncodingException
     */
    public static String newStringUtf16Be(final byte[] bytes) {
        return new String(bytes, Charsets.UTF_16BE);
    }

    /**
     * Constructs a new
     * <code>String</code> by decoding the specified array of bytes using the
     * UTF-16LE charset.
     *
     * @param bytes The bytes to be decoded into characters
     * @return A new <code>String</code> decoded from the specified array of
     * bytes using the UTF-16LE charset, or {@code null} if the input byte array
     * was {@code null}.
     * @throws NullPointerException Thrown if {@link Charsets#UTF_16LE} is not
     * initialized, which should never happen since it is required by the Java
     * platform specification.
     * @since As of 1.7, throws {@link NullPointerException} instead of
     * UnsupportedEncodingException
     */
    public static String newStringUtf16Le(final byte[] bytes) {
        return new String(bytes, Charsets.UTF_16LE);
    }

    /**
     * Constructs a new
     * <code>String</code> by decoding the specified array of bytes using the
     * UTF-8 charset.
     *
     * @param bytes The bytes to be decoded into characters
     * @return A new <code>String</code> decoded from the specified array of
     * bytes using the UTF-8 charset, or {@code null} if the input byte array
     * was {@code null}.
     * @throws NullPointerException Thrown if {@link Charsets#UTF_8} is not
     * initialized, which should never happen since it is required by the Java
     * platform specification.
     * @since As of 1.7, throws {@link NullPointerException} instead of
     * UnsupportedEncodingException
     */
    public static String newStringUtf8(final byte[] bytes) {
        return newString(bytes, Charsets.UTF_8);
    }
}
